rust-osdev/linked-list-allocator

[Feature request] Heap canary

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#58 opened on Apr 12, 2022

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help wanted

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Description

Recently I occurred a heap corruption bug in one of my real life projects:

Kernel panic - aborting: at /home/kazurin/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/linked_list_allocator-0.9.1/src/hole.rs:311: attempt to add with overflow

It took me long before I was able to discover the root cause, due to the complication of kernel debugging and the need to read the source code of various crates. It might be handy to have some simple heap canary mechanism (just like what Valgrind does) built into the allocator in such cases.

Features that I consider useful:

  • Ability to detect the corruption of heap control structures (namely the Holes) using some predefined magic bytes in the structure
  • Ability to reveal the corrupted structure's address in the panic message (for easier debugging)
  • Ability to verify the integrity of the whole heap at any time
  • The heap canary feature should be completely optional, in order not to cause preformance impact on production code

If such features are acceptable but not planned, perhaps I could do a PR in the future :)

Contributor guide

Research direction
Study the linked list allocator crate's HoleList and Hole structures. Understand how heap corruption can be detected by adding magic bytes to each Hole. Look at how Valgrind's heap canary works for inspiration. Focus on implementing a conditional compile time feature to enable canary checking without performance impact.
Tech stack
rust
Domain
operating systems
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Rustunsafe Rustmemory management
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35